The former Basel boss believes that the Dutchman's return to the Imtech Arena will reinvigorate his side, who have endured a frustrating start to the new Bundesliga season
The midfielder was signed from Tottenham Hotspur on deadline day, a move which saw him return to the club he left for Real Madrid in 2008.
The Dutchman made his first appearance of his second spell at the club in an 11-2 friendly victory of Niendorf, and the former Basel coach was delighted with his new player's impact.
"You saw a different team than they were a few weeks ago. We go onto the pitch with joy and have fun," told Bild after the match.
"Everyone saw that Van der Vaart was the boss on the pitch."
Van der Vaart scored 48 goals in 112 appearances during his first spell at the Imtech Arena.